Trauma Communication Center Coordinated Severity-Based Stroke Triage Acute stroke systems of care should emulate trauma systems which deliver the full range of care to all injured patients by means of organized, coordinated efforts in defined geographic areas. Just as trauma systems have proven ability to save lives of the most severely injured patients, we should have a stroke system able to provide care to patients with the most severe strokes. The most severe type of acute ischemic stroke is due to proximal large vessel occlusion (LVO). Mechanical thrombectomy (MT) offers an extraordinary potential to improve the outcome of patients with LVO. Unfortunately, in part because MT is available only at advanced stroke centers, only a minority of patients with LVO are treated with MT, and there are racial, socioeconomic, and rural disparities in access to MT. Based on the success of trauma systems and our prior collaboration, the Alabama Department of Public Health (ADPH) is planning a five-year statewide quality improvement initiative of trauma communications center (TCC) coordinated severity-based stroke triage (SBST) which aims to transform the fragmented acute stroke care system by coordinating prehospital and inter-facility emergency stroke care. This provides a ?natural experiment? allowing assessment of both the public health impact and the ?how and why? of implementation of an innovative acute stroke care model. We aim to (1) compare the proportion of patients encountered by the emergency medical service (EMS) with suspected LVO who are treated with MT before (adhering to standard triage to the nearest stroke center) and after implementation of TCC coordinated SBST; (2) assess the broad public health impact of TCC coordinated SBST by examining the reach and effectiveness of the intervention (including any differences by race, ethnicity, and population density), the fidelity of implementation, and ability to sustain the model in various settings; and (3) assess stakeholder perceptions of the intervention?s feasibility, appropriateness, and acceptability and identify barriers and facilitators to the intervention?s adoption, implementation, maintenance, and spread. This will guide future implementation efforts. To accomplish these aims, we will expand our successful model of TCC guided stroke severity assessment to all EMS regions in Alabama; use qualitative methods including interviews and focus groups to aid in the development of region and hospital specific prehospital and inter- facility stroke triage plans for patients with suspected LVO; and implement a phased rollout of TCC coordinated SBST across Alabama?s six EMS regions, lending itself to analysis of health processes and outcomes before and after the intervention in each region. To address implementation AIM 3, we will use a mixed methods approach using multiple methods consisting of surveys, interviews and focus groups. This project, if successful, can serve as a model for how the trauma system infrastructure that already exists in other regions and states can serve as the basis for a more integrated and effective system of emergency stroke care.